U.S. patent application number 11/908165 was filed with the patent office on 2008-08-07 for effluent purifying plant with centralized structure.
Invention is credited to Bernard Beaulieu.
Application Number | 20080185321 11/908165 |
Document ID | / |
Family ID | 35170000 |
Filed Date | 2008-08-07 |
United States Patent
Application |
20080185321 |
Kind Code |
A1 |
Beaulieu; Bernard |
August 7, 2008 |
Effluent Purifying Plant with Centralized Structure
Abstract
The invention concerns a plant comprising, on a vertical axis, a
homogenizing vessel (1) followed by a settling vessel (2) and a
flocculating vat (3). The homogenizing vessel (1) is fed by
tangential intake (92) of the effluent and the input (611) and the
output (612) of the upper tube (61) comprise a helical guide (613,
614) for driving the effluent in rotation. The lower tube (62) of
larger diameter than that of the upper tube (61) is terminated by
an outlet in the form of an upside-down cone (622) with reduced
cross-section (621). The lower portion (31) of the flocculation vat
(3) is truncated, with an apex angle, smaller than that of the
upper portion (32), said lower portion being parallel to the cone
of the outlet of the lower tube (62), and anti-backflow cones (7,
8) surround the conduit (6) in the settling vessel (2).
Inventors: |
Beaulieu; Bernard;
(Chassiers, FR) |
Correspondence
Address: |
BAKER & DANIELS LLP;111 E. WAYNE STREET
SUITE 800
FORT WAYNE
IN
46802
US
|
Family ID: |
35170000 |
Appl. No.: |
11/908165 |
Filed: |
March 7, 2006 |
PCT Filed: |
March 7, 2006 |
PCT NO: |
PCT/FR2006/050199 |
371 Date: |
November 9, 2007 |
Current U.S.
Class: |
210/88 ;
210/202 |
Current CPC
Class: |
B01D 21/2444 20130101;
B01D 21/245 20130101; C02F 1/5281 20130101; B01D 21/2427 20130101;
B01D 21/2411 20130101; B01D 21/0039 20130101; B01D 21/08 20130101;
C02F 3/00 20130101; C02F 1/686 20130101; B01D 21/0012 20130101;
B01D 21/0018 20130101; B01D 21/0042 20130101 |
Class at
Publication: |
210/88 ;
210/202 |
International
Class: |
B01D 21/01 20060101
B01D021/01 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 16, 2005 |
FR |
05 50 670 |
Claims
1. An effluent purifying plant with centralized structure
comprising, on a vertical axis, a homogenizing vessel (1) receiving
the effluent with the addition of a coagulating or flocculating
agent, a settling vessel (2) beneath the homogenizing vessel (1), a
flocculating vat (3) comprising a frustoconical upper portion (31)
extended by a lower portion, which vat is placed inside the
settling vessel (2) and in which sludge flakes form, a pipe (6)
arranged in the axis (ZZ), leading downwards, connecting the
homogenizing vessel (1) to the lower part of the flocculating vat
(3) through which the effluent passes from bottom to top and is
clarified in contact with the sludge flakes, the pipe (6)
comprising an upper tube, one end of which opens into the
homogenizing vessel and the other end of which opens into a lower
tube of larger diameter than that of the upper tube, the lower end
thereof opening into the lower part of the flocculation vat, the
lower portion of the settling vessel having a frustoconical portion
forming the sludge vat (4) which receives the sludge overflowing
from the flocculating vat (3), an annular vessel surrounding the
settling vessel and receiving the filtered water by overflow from
the settling vessel (2), characterized in that the homogenizing
vessel (1) has a tangential intake (91) for the effluent, the inlet
(611) and the outlet (612) of the upper tube (61) include a helical
guide (613,614) for setting the effluent in rotation, the lower
tube (62) of larger diameter than that of the upper tube (61) is
terminated by an outlet in the form of an upside-down cone (622)
with reduced cross-section (621), the lower portion (31) of the
flocculating vat (3) is frustoconical, with an apex angle smaller
than that of its upper portion (32), the lower portion (31) being
parallel to the cone of the outlet of the lower tube (62), and at
least one anti-backflow cone (7,8) surrounds the pipe (6) in the
settling vessel (2).
2. A plant according to claim 1, characterized by a second
anti-backflow cone (8) arranged above the flocculating vat (3).
3. A plant according to claim 1, characterized in that the outlet
of the settling vessel (2) has stabilising baffles (24) for the
liquid and a peripheral distribution of outlet openings (23), the
annular vessel (5) surrounding the settling vessel (2) contains a
filter-mass (511) in the upper portion (51), its lower portion (52)
constituting the storage volume for the filtered water.
4. A plant according to claim 1, characterized in that the taper of
the upper portion (31) of the flocculating vat (3) is greater than
that of its lower portion (32).
5. A plant according to claim 1, characterized in that the lower
tube (62A) is in the shape of two truncated cones (62A, 622) which
are assembled by their major base, the inlet cross-section
corresponding to that of the upper tube (61) to continue by flaring
out, and an injection means (624) injects a flocculating agent in
the middle of this volume.
6. A plant according to claim 1, characterized by a metering means
(93) for metering the reagent or reagents is provided upstream of
the homogenising vessel (1) and this metering means is followed by
a static mixer (94).
7. A plant according to claim 1, characterized in that the annular
vessel (5) is composed of a lower portion (51A) surrounding the
lower portion (22) of the settling vessel (2), and of an upper
portion (51A) containing the filter-mass (511A) installed above and
in prolongation of the settling vessel (2) and having the same
outer wall (54A), these two portions being connected by a pipe, an
annular channel (211) surrounding the pipe (6) to connect the upper
volume (21) of the settling vessel (2) to irrigation ramps (27A)
opening out above the filter-mass (511A).
8. A plant according to claim 1, characterized by a collecting
chamber (213) which separates the upper portion (51A) from the
upper volume (21) of the settling vessel (2), the collecting
chamber (213) being connected to the lower portion (52A) by a pipe
equipped with a valve (215).
9. A plant according to claim 1, characterized by an annular
pre-treatment vessel (11), surrounding the outer vessel (5), and
composed of a lower volume (113) in which the effluent arrives with
the addition of a coagulating and/or flocculating agent in order to
deposit the sludge flakes there, and of an upper volume (112) in
which the partially clarified liquid rises in order to be
transferred into the distribution vessel (13).
10. A plant according to claim 9, characterized in that the annular
pre-treatment vessel (11) comprises a flocculating vat (115) formed
of an annular plate (115A) provided with frustoconical cavities
(115B) bordered by passage openings (115C), a pipe (116) coming
from an effluent distribution chamber (113) opening into each
cavity (115B), and the lower volume is bordered by a bottom (114)
in the shape of an annular collar constituting the sludge storage
vat (114).
11. A plant according to claim 9, characterized in that the lower
volume (113) of the vessel (111) is separated from its upper volume
(112) by a partition (118) provided with openings (119), the inlet
of which is defined by divergent cones (119A), these openings (119)
being offset angularly in relation to the angular position of the
flocculation cavities (115B) so as to occupy an intermediate
position in each case.
12. A plant according to claim 1, characterized in that it
comprises a complementary bacteriological treatment portion (200)
composed of a series of annular chambers (201, 202, 203)
surrounding the outer vessel (11) and receiving the cleansed
liquid, which passes through these chambers (201, 202, 203)
connected in a cascade by communication pipes (205, 206, 207),
being provided with helical guides (210) for setting in rotation
the stream of liquid and suspended particles constituting the
charge of each chamber, the communication pipes (205, 206, 207)
being U-shaped tubes, the inlet arm (205E) of which faces
downstream in the upstream chamber in order to open out through an
outlet (205S) facing downstream in the following annular chamber,
in the direction of flow of the liquid in these chambers.
13. A plant according to claim 12, characterized in that the outlet
arm (205S) of the communication pipe (205, 206, 207) includes a
helical guide (211).
Description
FIELD OF THE INVENTION
[0001] The present invention concerns an effluent purifying plant
with centralized structure comprising, on a vertical axis, [0002] a
homogenizing vessel receiving the effluent with the addition of a
coagulating or flocculating agent, [0003] a settling vessel beneath
the homogenizing vessel, [0004] a flocculating vat comprising a
frustoconical upper portion extended by a lower portion, which vat
is placed inside the settling vessel and in which sludge flakes
form, [0005] a pipe arranged in the axis, leading downwards,
connecting the homogenizing vessel to the lower part of the
flocculating vat through which the effluent passes from bottom to
top and is clarified in contact with the sludge flakes, [0006] the
pipe comprising an upper tube, one end of which opens into the
homogenizing vessel and the other end of which opens into a lower
tube of larger diameter than that of the upper tube, the lower end
thereof opening into the lower part of the flocculating vat, [0007]
the lower portion of the settling vessel having a frustoconical
portion forming the sludge vat which receives the sludge
overflowing from the flocculating vat, [0008] an annular vessel
surrounding the settling vessel and receiving the filtered water by
overflow from the settling vessel.
[0009] A plant of this type is already known from the document FR
00 07 42 (FR 2 810 310).
AIM OF THE INVENTION
[0010] The aim of the present invention is to develop an effluent
purifying plant of the type defined above permitting improved
management of the dynamic flow by improved distribution and
utilisation of the injection of the coagulating agent, acceleration
of the coagulation phenomenon by avoiding premature flocculation in
the mixing vat, or preventing the bed of sludge from interfering
with flocculation and avoiding disturbing flocculation by the rise
of the clarified liquid while also permitting bacteriological
treatment of the clarified liquid, with very compact means
occupying the minimum ground surface area.
STATEMENT AND ADVANTAGES OF THE INVENTION
[0011] To this end, the invention concerns an effluent purifying
plant with centralized structure of the type defined above,
characterized in that [0012] the homogenizing vessel has a
tangential intake for the effluent, [0013] the inlet and the outlet
of the upper tube include a helical guide for setting the effluent
in rotation, [0014] the lower tube of larger diameter than that of
the upper tube is terminated by an outlet in the form of an
upside-down cone with reduced cross-section, [0015] the lower
portion of the flocculating vat is frustoconical with an apex angle
smaller than that of its upper portion, the lower portion being
parallel to the cone of the outlet of the lower tube, and [0016] at
least one anti-backflow cone surrounds the pipe in the settling
vessel.
[0017] In general terms, the plant according to the invention
permits excellent management of the flows, no matter what the
nature of the effluents, thereby considerably simplifying the
setting-up of the plant and its use while reducing the operating
costs and the consumption of coagulating and flocculating
agents.
[0018] Owing to the distribution of the effluent at the point of
injection of the coagulating and/or flocculating agent, especially
by injecting the flocculent upstream of a static mixer and owing to
a tangential intake in the homogenizing vessel, the flocculating
agent can be distributed more efficiently and therefore the
quantities consumed reduced. The means of the invention make it
possible to maintain the liquid in rotation on itself by the vortex
effect, thereby avoiding any untimely deposit of flakes capable of
clogging parts of the plant. The sludge flakes are deposited in the
sludge vat without interfering with the rise of the liquid or
disturbing the flocculation downstream.
[0019] The bottom of the flocculating vat facilitates the
circulation and rise of the effluent charged with flocculating
agents so that the sludge flakes develop, rise towards the upper
portion of the flocculating vat and then pass into the sludge vat
either by overflow or through openings provided for this
purpose.
[0020] The anti-backflow cone or cones also facilitate the
flocculation and release of the sludge flakes towards the sludge
vat, preventing the sludge flakes from collecting together in the
centre of the plant and gradually clogging the latter by spreading
outwards.
[0021] According to another advantageous feature, a second
anti-backflow cone is arranged above the flocculating vat and this
second cone is adjustable. The adjustment makes it possible to
adapt the effect of the anti-backflow cone to the physical/chemical
characteristics of the effluent.
[0022] The anti-backflow cone or cones also facilitate the
preferential circulation of the water first of all charged with
sludge flakes and then of the clarified water, in the part above
the area of formation and retention of the sludge flakes. The
clarified water is then forcibly distributed at the surface of the
filter-mass in order to avoid any formation of a preferential
passage through the filter-mass.
[0023] According to another advantageous feature, [0024] the outlet
of the settling vessel has stabilising baffles for the liquid and
peripheral distribution of outlet openings, [0025] the annular
vessel surrounding the settling vessel contains a filter-mass in
the upper portion, its lower portion constituting the storage
volume for the filtered water.
[0026] Owing to the baffles, the regulation of the flow rate and
rendering the distribution of the flows towards the filter-mass
uniform make it possible to eliminate at least 95% of the residual
matter in suspension.
[0027] According to another advantageous feature, the taper of the
upper portion of the flocculating vat is greater than that of the
its lower portion.
[0028] This double frustoconical shape prevents the accumulation of
sludge in the angles of the lower truncated cone and the liquid
accelerates along the outer wall. Then, the more flared
frustoconical shape directs the flow outwards, winding round the
area of stagnant liquid around the pipe and beneath the
anti-backflow cone.
[0029] According to another advantageous feature, the lower tube is
in the shape of two truncated cones assembled by their major base,
the inlet cross-section corresponding to that of the upper tube to
continue by flaring out, and an injection means injects a
flocculating agent in the middle of this volume.
[0030] This embodiment is particularly advantageous in the case of
weakly charged effluents, such as for example river water to be
transformed into potable water.
[0031] The double cone with a wide central portion at which the
flocculating agent is injected makes a thorough mixing of the
flocculating agent and the effluent possible so that flocculation
takes place within this limited enclosure in which the speed of
passage of the effluent is reduced, the effluent being always in
rotation about the axis of the plant.
[0032] Flocculation is substantially terminated at the outlet of
the double cone. Then, during the rise of the flow in the vessel,
the flakes collect together in order to be deposited in the sludge
vat.
[0033] According to another advantageous feature, a means for
metering the reagent or reagents is provided upstream of the
homogenising vessel and this metering means is followed by a static
mixer.
[0034] According to another advantageous feature, the annular
vessel is composed of a lower portion surrounding the lower portion
of the settling vessel, and an upper portion containing the
filter-mass installed above and in prolongation of the settling
vessel and having the same outer wall, these two portions being
connected by a pipe, an annular channel surrounding the pipe to
connect the upper volume of the settling vessel to irrigation ramps
opening out above the filter-mass.
[0035] This solution is particularly advantageous because of the
compactness of the plant and the volume available for collecting
the treated water.
[0036] The cleansed liquid which rises in the annular channel
circulates at an extremely reduced speed. In addition, a cone
placed at the inlet of the annular channel prevents any sludge
flakes which might float at the upper wall of the flocculating vat
from being likely to pass into the annular channel. Thus, this cone
has not only a separating and retaining effect, but also a guiding
effect, creating a very slow circulation like a damming means, so
that the flakes which may be floating in the upper portion of this
volume are redirected downwards and gradually descend into the
sludge vat while adhering to any other possible sludge flakes.
[0037] In the case of this improvement, advantageously, a
collecting chamber is provided which separates the upper portion
from the upper volume of the settling vessel, the collecting
chamber being connected to the lower portion by a pipe equipped
with a valve.
[0038] It is also of advantage to treat the effluent by means of a
pre-treatment before introducing it into the actual plant described
above, in order to avoid causing excessive stress on the plant.
[0039] To this end, the plant includes an annular pre-treatment
vessel, surrounding the outer vessel, and composed of a lower
volume in which the effluent arrives with the addition of a
coagulating and/or flocculating agent in order to deposit the
sludge flakes there, and of an upper volume in which the partially
clarified liquid rises in order to be transferred into the
distribution vessel.
[0040] In particular, the annular pre-treatment vessel comprises a
flocculating vat formed of an annular plate provided with
frustoconical cavities bordered by passage openings, a pipe coming
from an effluent distribution chamber opening into each cavity, and
the lower volume is bordered by a bottom in the shape of an annular
collar constituting the sludge storage vat.
[0041] According to another feature, the lower volume of the vessel
is separated from its upper volume by a partition provided with
openings, the inlet of which is delimited by divergent cones, these
openings being offset angularly in relation to the angular position
of the flocculation cavities so as to occupy an intermediate
position in each case.
[0042] This pre-treatment with decantation makes it possible not
only to eliminate a considerable part of the charge of the
effluent, but above all such elimination facilitates the treatment
of the effluent by the central portion of the plant already
mentioned above, since the effluents arriving in this central
portion will thus all have substantially related
characteristics.
[0043] The plant also permits bacteriological treatment of the
liquid at the outlet of the decanting and filtering portion, and
for this purpose the plant includes a complementary bacteriological
treatment portion composed of a series of annular chambers
surrounding the outer vessel and receiving the cleansed liquid,
which passes through these chambers connected in a cascade by
communication pipes, being provided with helical guides for setting
in rotation the stream of liquid and suspended particles
constituting the charge of each chamber, the communication pipes
being U-shaped tubes, the inlet arm of which faces downstream in
the upstream chamber in order to open out through an outlet facing
downstream in the following annular chamber, in the direction of
flow of the liquid in these chambers.
[0044] The effectiveness of the bacteriological treatment plant
permits a significant reduction in the materials used, and
consequently a reduction in the operating costs of the plant.
DRAWINGS
[0045] The present invention will be described below in more detail
by means of exemplary embodiments shown diagrammatically in the
appended drawings, in which:
[0046] FIG. 1 is a view in axial section of a first embodiment of
an effluent purifying plant,
[0047] FIG. 2 shows a first variant of the effluent purifying
plant, especially for the production of potable water,
[0048] FIG. 3 is a sectional view analogous to that of the
preceding figures of another embodiment of an effluent purifying
plant including a pre-treatment section,
[0049] FIG. 3A is a simplified view in axial section showing the
pre-treatment section of the variant of FIG. 3,
[0050] FIG. 3B shows in a top view the annular plate supporting the
flocculating vats,
[0051] FIG. 3C is a top view of the annular plate separating the
lower volume from the upper volume of the outer annular vessel,
[0052] FIG. 4 is a view in axial section of another embodiment of
an effluent purifying plant equipped not only with the
pre-treatment section but also with a bacteriological treatment
means,
[0053] FIG. 4A is an extract from FIG. 4 showing the
bacteriological treatment portion of the plant,
[0054] FIG. 4B is a partial view of the connection between two
annular chambers of the bacteriological treatment portion of the
embodiment of the effluent purifying plant according to FIG. 4.
DESCRIPTION OF EMBODIMENTS
[0055] According to FIG. 1, the invention concerns an effluent
purifying plant with centralized structure. The plant, distributed
schematically about a vertical axis ZZ, preferably in rotational
symmetry, is composed of a homogenizing vessel 1 receiving the
effluent to be treated. Beneath the homogenizing vessel there is a
settling vessel 2 in which a flocculating vat 3 is located, and the
space between the settling vessel 2 and the flocculating vat 3
constitutes the sludge vat 4, the upper portion 21 forming the
actual settling volume; around the settling vessel 2, an annular
vessel 5 receives the filtered water by overflow from the settling
vessel 2. An immersion pipe 6 arranged in the axis ZZ descends
through the homogenizing vessel 1 as far as the lower part of the
flocculating vat 3. The effluent receives flocculating and
coagulating agents. By the effect of rotation it circulates in the
homogenizing vessel 1 then into the pipe 6 descending through the
settling vessel 2 and the flocculating vat 3, in order to rise up
there, release sludge flakes FB and allow the filtered water to be
collected. The settling vessel 2 has at least one anti-backflow
cone 7, 8 surrounding the pipe 6 and pushing back the sludge
flakes, floating in the ascending flow of filtered effluent/water,
which rises to the top 21 of the settling vessel 2.
[0056] The circulation of the liquid (effluent or filtered liquid,
filtered water) is indicated by arrows without reference numbers.
Circulation takes place either on a more or less straight path, or
according to curved arrows indicating a rotational movement of the
liquid. There are also return or winding movements for example
below the anti-backflow cone or cones 7, 8.
[0057] The different vessels 1, 2, 3 and pipe 6 are connected and
supported by means that are neither shown nor described, since they
are customary means of construction. All that is important is the
arrangement grouped and centred about the axis ZZ so that the plant
occupies the least possible ground surface area and volume for a
maximum capacity of effluents and filtered liquids.
[0058] In more detail, the effluent purifying plant shown in
section, especially in axial section in FIG. 1, will be explained
hereinafter.
[0059] The homogenizing vessel 1 located in the upper portion of
the plant is equipped with an effluent intake 9. The pipe 91 of
this intake opens tangentially into the homogenizing vessel 1 in
order to induce a rotational movement of the liquid therein.
Upstream of the homogenizing vessel 1, the effluent pipe 91 coming,
for example, from a pump 92, has an injection point 93 for
coagulant/flocculant. The injection point 93 is followed by a
static mixer 94 in the form of a chamber which slows down the fluid
flow rate by means of an increase in the cross-section in order to
facilitate mixing between the effluent and the injected
coagulating/flocculating agents.
[0060] The settling vessel 2 which is located beneath the
homogenizing vessel 1 also has a rotationally symmetrical shape
with respect to the axis ZZ. The vessel 2 is composed overall of a
substantially cylindrical, circular, upper portion 21, and of a
frustoconical lower portion 22.
[0061] The lower portion 22 houses the flocculating vat 3, and the
upper portion 21 forming the volume providing the actual settling
function houses one, and preferably two, anti-backflow cones 7, 8.
One (7) of the cones is fixed, the other (8) is adjustable. The two
cones 7, 8 are centred on the axis ZZ and surround the effluent
pipe 6 descending from the homogenizing vessel 1 almost to the
bottom of the flocculating vat 3.
[0062] The flocculating vat 3 does not abut with the upper edge of
its side 31 the side of the lower portion 22 of the settling vessel
2, but leaves a gap and an annular volume as well as a lower volume
beneath the flocculating vat 3 (this latter rests on feet in the
settling vessel) to form a sludge collecting chamber or sludge vat
4. The bottom of this vat 4 is connected to a sludge discharge pump
10. The pump 10 is controlled or programmed to discharge the sludge
according to its accumulation or periodically.
[0063] The effluent pipe 6 is preferably installed according to the
axis ZZ, that is, according to the axis of symmetry of the
structure of the plant. The descending pipe 6 is composed of a
first tube 61 opening into the homogenizing vessel 1, rising up in
this latter so as to delimit therein an annular volume facilitating
the setting in rotation of the effluent arriving and rotating in
the homogenizing vessel 1.
[0064] The upper tube 61 descends through the upper portion 21 of
the settling vessel 2 to meet a lower tube 62 forming part of the
pipe 6. The lower tube 62 opens out close to the bottom of the
flocculating vat 3. The lower tube 62 extends the upper tube 61 and
has a diameter significantly larger than that of the upper tube.
Both at its entry 611 into the homogenizing vessel 1 and at its
outlet 612 into the lower tube 62, the upper tube 61 includes in
each case a helical guide 613, 614 in the form of a vane,
incorporated in the end of the tube 61 so as to impart a rotational
impulse to the effluent which passes through the upper tube 61.
[0065] This rotational movement of the effluent continues through
the lower tube 62 which is terminated by a narrowed outlet 621
constituted by a truncated cone, the apex of which faces downwards.
At the base of the truncated cone 622, the lower tube 62 has a
support 623 equipped with an injection point for a flocculating
agent 624.
[0066] The flocculating vat 3 into which the pipe 6 opens and, more
precisely, its rotationally symmetrical lower tube 62, is formed by
the combination of two frustoconical shapes 31, 32, a very flared
frustoconical upper portion 31 and a less flared frustoconical
lower portion 32. The truncated cone 622 terminating the lower
portion of the lower tube 62 of the pipe 6 and the truncated cone
32 constituting the lower portion of the flocculating vat 3 are
preferably parallel, so as to regularize the flow emerging from the
opening 622 of the tube 62 in order to rise up in the flocculating
vat. On the other hand, the upper truncated cone 31 of the
flocculating vat 3 is very widely flared, so as to slow down the
flow velocity of the ascending flow in order to facilitate the
formation of sludge flakes which collect together and gradually
rise up, entrained by the liquid of the flocculating vat. Then, the
large sludge flakes FB pass over the edge of the vat 3 and, since
the speed of the liquid at this location is very slow, the flakes
descend into the sludge vat 4 and accumulate at the bottom.
[0067] One (7) of the anti-backflow cones is located just above the
flocculating vat 3. It is a frustoconical surface engaged both on
the lower tube 62 of the pipe 6 and around the lower end of the
upper tube 62. This anti-backflow cone 7 serves to stabilise the
flow of effluent rising up in the flocculating vat 3, in proximity
to the outer wall of the lower tube 62.
[0068] The cone 7 thus creates a ring of more or less immobile
liquid surrounding the lower tube so that any flakes located in
this area circulate very slowly and therefore have a tendency to
drop down again, while the flakes entrained by the circulation of
the liquid arriving from the pipe 6 pass preferentially towards the
collar of the flocculating vat 3.
[0069] Above this first cone 7 there is a second cone 8 located
clearly in the upper volume 21 of the settling vessel 2, that is,
the actual settling volume, again in such a way as to stabilise the
flow in order to facilitate the circular rising/falling movement of
any streams of cleansed liquid, in order to eliminate therefrom the
last particles or flakes of sludge. This cone 8 is adjustable in
height in the settling volume 21 of the vessel 2.
[0070] The vertical positioning of the cone 8 depends on the
residual density of the sludge flakes entrained in the ascending
flow of the clarified water and is intended to regulate the
ascending speed of the flow in order to obtain the precipitation of
the flakes.
[0071] For the following adjustment, the type of effluent to be
treated, knowing the behaviour of the flakes, and according to the
flow rate to be treated, pre-adjustment is carried out in the
workshop and the final positioning is carried out in situ after the
setting up of the whole of the plant.
[0072] In its upper portion 21, the settling vessel 2 is equipped
with a peripheral distribution of overflow openings 23. Beneath
these openings 23, inside the settling vessel 2, there is an
assembly of very slightly inclined baffles 24. The filtered water
which rises up again in the settling vessel 2 passes between the
baffles 24 then through the openings 23.
[0073] In order to facilitate the distribution of the filtered
water in the vessel 5, the ejection openings 23 each open
preferably into an elbow 27 terminated by a sprinkler rose so as to
cause the liquid to drip or trickle onto a relatively large surface
area of the filter-mass 511 and avoid preferential passages.
[0074] The settling vessel is in fact surrounded by the annular
vessel 5, the lower portion 52 of which makes it possible to
receive the filtered water, and the upper portion 51 contains a
filter-mass supported by a partition 53 separating the upper
portion 51 and the lower portion 52.
[0075] The annular vessel 5 substantially follows the contours of
the settling vessel 2. It is bounded by an outer wall, the lower
portion 55 of which is frustoconical and the upper portion 54
cylindrical.
[0076] The horizontal partition 53 in the form of an annular collar
is pierced by holes to allow the water which has passed through the
filter-mass 511 to descend into the lower portion 52, whence it can
be extracted by a pump 12.
[0077] The baffles 24 of the settling vessel 2 are equipped with
cleaning ramps 26 connected to a water source, for example of
filtered water, and below the filter-mass 511, above the partition
53, strainers 56 allow water to be injected, if necessary, charged
with gas for cleaning the filter-mass 511 by reverse
circulation.
[0078] FIG. 2 shows a first variant of the plant of FIG. 1. This
variant repeats the main elements of the first embodiment, and
these elements bear the same references without their description
being repeated in detail. The elements which are analogous but
particular to this variant will bear the same references with the
addition of the suffix A.
[0079] Thus, the lower tube 62A of the pipe 6 is formed by a flared
portion in the shape of a truncated cone to which is connected, in
an inverted position, the truncated cone 622; these two truncated
cones joined by their major base include at the join the support
623 equipped with the injection point for flocculating agent
624.
[0080] The flocculating vat 3 has the same shape as that of the
first embodiment, except that, close to its upper edge, it has
openings 33 for the passage of the sludge flakes which will no
longer pass over the upper edge. These openings 33 open into the
sludge vat 4 formed as previously between the flocculating vat 3
and the lower portion 22 of the settling vessel 2. The extraction
of the sludge is again effected by a pump or a valve 10 in the
lower portion of the sludge vat 4.
[0081] The principal modifications of this variant concern the
vessel receiving the filtered effluent or clarified water. This
vessel is divided into two parts, an upper portion 51A installed
above the settling vessel 2 and in prolongation of this latter,
sharing with the upper volume 21 of the settling vessel 2 the same
circular cylindrical wall. The second part or lower portion 52A of
the vessel receiving the filtered water is located in the lower
part around the lower portion 22 of the settling vessel. The lower
portion 52A shares with the settling vessel the common wall 22. It
is bounded externally by a circular cylindrical wall 55A with a
bottom and a top.
[0082] The lower portion 52a is connected to the pump 12 for
drawing off the filtered liquid (filtered water).
[0083] The intake for the upper portion 51a of the vessel is
provided by an annular channel 211, surrounding the upper tube 61
of the pipe 6. The annular channel 211 has an inlet in the upper
volume 21 formed by a cone 212 also intended to stabilise the flows
like the anti-backflow cones 7 and 8. In the upper portion the
annular channel 211 has openings 23A comparable to the overflow
openings 23 of FIG. 1 which open into irrigation ramps 27A
distributing the filtered liquid over the filter-mass 511A. The
filter-mass 511A is located above the partition bounding the
collecting chamber 213 collecting the filtered liquid at the outlet
of the upper portion 511A. This chamber 213 is connected by a pipe
214, equipped with a valve 215, to the lower portion 52A. The valve
215, preferably remote-controlled, makes it possible to discharge
the liquid emerging from the filter-mass 511A, continuously or
discontinuously.
[0084] The cleansing of the filter-mass 511A is carried out by
countercurrent or reverse flow by means of strainers 56A that are
installed at the base of the filtering material in the upper
portion 51A and are fed by a pipe 122 coming from a three-way valve
121 at the outlet of the draught pump 12. The valve 121, normally
connected to the outlet 124 for drawing off filtered water, may be
switched in order to send the filtered water back through the
strainers 56A and the filter-mass 511A, the water then circulating
in the reverse direction being discharged by means not shown.
[0085] The plant thus described is suited quite particularly to the
production of potable water.
[0086] FIG. 3 shows an alternative embodiment corresponding
substantially to FIG. 1, with the addition of means making it
possible to decant the effluent before its entry into the actual
plant through the homogenizing vessel 1.
[0087] Thus, the concentric structure of the effluent purifying
plant described above is surrounded externally by another annular
structure forming an outer vessel 11 for pre-treatment and partial
settling. This annular outer vessel 11 is bounded by an outer,
circular cylindrical wall 111 forming an upper volume 112 and a
lower volume 113, this latter benefitting from the increase in
volume provided within the circumscribed perimeter, owing to the
frustoconical shape of the lower portion 55 of the annular chamber
5 surrounding the settling vessel 2.
[0088] The outer annular vessel 11 makes it possible to decant a
significant portion of the solid matter in the form of sludge or
flakes and, for this purpose, its lower volume 113 is bounded by an
annular collar 114 forming the bottom of the outer annular vessel.
Above the annular collar 114, for example toroidal in form and of
semi-circular cross-section, there is a flocculating vat 115 formed
by an annular plate 115A equipped with frustoconical cavities 115B,
into which descending pipes 116 open. The frustoconical cavities
115B are bordered by openings 115C through which the sludge flakes
descend into the sludge vat 114. For the purpose of simplification,
these different means will be termed: flocculating vat 115. The
pipes 116 are connected in the upper portion of the plant to a
distribution vessel 13, itself fed with effluent by a pump 14 and a
pipe 15 with, preferably, an injection point 151 for coagulating
agent, followed by a chamber forming a static mixer 152, then an
injection point 153 for flocculating agent, followed also by a
chamber forming a static mixer 153 for opening into the
distribution vessel 13. A plurality of pipes 116 depart from the
distribution chamber 13 in radial directions to descend to the
bottom of the flocculating vat 115 through a slightly divergent
form of pipe 117 so as to slow down the speed of the effluent.
[0089] At this level, significant flocculation occurs, and may
represent from 30 to 40% of the sludge in suspension in the liquid
to be cleansed. The sludge overflows from the flocculating vat 115
to reach the sludge storage vat 114 formed by the annular collar
whence the sludge is pumped.
[0090] The effluent is fed in by the pump 14 and the purified water
is extracted by the pump 12. The lifting pump 92 takes up the
effluent that has undergone the first decantation of its sludge
flakes in the outer annular vat 11. The effluent arriving in the
lower portion 113 of the annular vessel 11 rises up to pass into
the upper volume 112 forming the annular buffer chamber located
above the partition 118 dividing the outer annular vessel 11.
Communication between these two annular volumes is provided by
openings 119 distributed in the partition 118 and the inlet of
which is preceded by a divergent cone 119A.
[0091] The cleansing of the filter-mass 511 of the annular chamber
5 receiving the filtered water is effected by sending filtered
water in the reverse direction from the normal direction of passage
of the water through the filter-mass. This water is introduced, in
the lower part at the lower partition 53, through the strainers 56.
The water thus injected for cleansing the filter-mass 511 is
preferably water recovered in the filtered water storage area. The
water is fed in preferably by the same pump as that which extracts
the filtered water from the enclosure 52. A system of valves makes
it possible to circulate the water for cleansing the filter-mass
solely through the mass and not through the homogenizing
vessel.
[0092] FIG. 3A shows in isolation the addition to the plant of FIG.
3 in relation to the basic plant shown in FIG. 1.
[0093] FIG. 3B shows in more detail the shape of the flocculating
vat 115 provided in the actual annular plate 115A. The
frustoconical cavities are each fed by a pipe 116 departing from
the distribution chamber 13. This view shows the distribution of
the openings 115C around each cavity 115B for the passage of the
sludge flakes emerging from the cavity 115B.
[0094] In its portion separating two cavities 115B, the collar 115A
is traversed by oblong and/or round passages permitting the calm
rise of the liquid of the sludge vat 115.
[0095] FIG. 3C shows the outer vessel 11 sectioned above the
partition 118, showing this latter and also the openings 119
bordered by the inlet cones 119A. The figure also shows the pipes
116, emphasising the angular off-set between on the one hand the
pipes 116 (the cavities 115B associated but not shown in this
figure) and on the other hand the openings 119 occupying
intermediate positions.
[0096] FIG. 4 shows another variant of the plant of FIG. 1 or of
that with the addition of FIG. 3 with, in addition, means for
bacteriological treatment of the filtered effluent, at the outlet
of the plant of FIG. 3. As above, the elements identical or
analogous to those already described bear the same references and
their description will not be repeated.
[0097] Half of the complementary part added to the plant of FIG. 3A
is shown in isolation in FIG. 4A.
[0098] This complementary part 200 is composed of a series of
annular or toroidal chambers 201, 202, 203, surrounding the outer
vessel 11 and arranged in a cascade to receive the purified liquid
coming from the lower portion 52 of the vessel 5. The liquid
(water) is pumped by the pump 12, but instead of being supplied
outside, it feeds the cascade of toroidal chambers 201-203 in
succession from bottom to top. The toroidal chambers have inner
helical guides for imparting to the stream of fluid a rotational
movement about its axis of movement. These chambers contain charges
which remain in suspension owing to this movement of displacement
and rotation of the fluid which passes through them. The chambers
communicate with one another through a U-shaped communicating pipe
205, 206, 207, the inlet of which in each case faces downstream
according to the circulating movement of the liquid (arrow L) and
its charge of particles in the corresponding annular chamber in
order to extract liquid therefrom according to the arrival of
untreated liquid in the annular chamber without removing from it
the charge of particles in suspension and to pass it into the
following chamber.
[0099] Finally, the last chamber 204 located in the top part serves
for drawing off the purified liquid.
[0100] FIG. 4B shows the detail of the joining of two annular
chambers, for example the chambers 201, 202, by a U-shaped pipe
205, the inlet 204E of which opens into the chamber 201 facing
downstream in the direction of circulation of the liquid
represented by the arrow L inside the chamber 201. Upstream of the
inlet 205E, the chamber 201 has a helical guide 210 in the shape of
an insert intended to impart to the stream of fluid circulating in
the chamber a rotational component about the axis of the chamber. A
plurality of such guides may be distributed inside the chamber 201,
as also in the other chambers such as the chamber 202.
[0101] The connecting pipe 205 opens into the downstream chamber
202 through its outlet 205S, also preferably provided with a
helical guide 211, imparting to the liquid opening into the chamber
202 a rotational movement about its axis. The rotational movement
is amplified by the helical guide 10 which is located
downstream.
* * * * *